As a modern trend, oil and gas producers have turned to a process known as Hydraulic Fracturing, of “fracing,” in order better develop tight-gas reservoirs in deep rock formations. The fracing process is used pervasively throughout the industry (for example, the Barnett Shale, Marcellus Formation, and Eagle Ford Formation areas in North America) because it is an efficient and economically beneficial process of extracting oil and gas from deep rock formations. During the fracing process, oil and gas producers employ the use of a fracturing fluid, such as water, oil, or acid, in order to improve oil and gas production through wellbore drilling in reservoir rock formations. The fracturing fluid can be used to fracture rock layers and release oil and natural gas stored within the multiple layers of rock. To increase its effectiveness, fracturing fluid often comprises a propping agent used to hold open cracks in rock formations after hydraulic pressure dissipates. By holding open these cracks for an extended period of time, producers can realize increased natural resource yields during the fracing process.
The fracing process is typically carried out by injecting large volumes of highly-pressurized fresh water into a well in order to induce structural cracks known as fractures. Prior to injection, the water is generally treated with a friction reducer, biocides, scale inhibitors, or surfactants. The injected water often contains a propping agent, such as sand, to hold open the fractures formed by the injected water to maximize the extraction of the natural resources. Once the fracing process is complete, the fracturing fluid is returned to the surface along with both the natural salt water found in the oil and gas reservoir, and the extracted oil and gas targeted by the fracing process. This combined fluid is often referred to as fracture return water or “Frac water.”
Frac water can be susceptible to contamination by virtue of its exposure to bacteria and other pathogens during the fracing process. Accordingly, the Frac water returning to the surface can be potentially dangerous to the environment if it is not recovered and disposed of properly. Moreover, these bacterial and pathogenic contaminates can prohibit a well producer from reusing the Frac water after the initial fracing. This resulting waste can add significant costs to the drilling operation. For example, horizontal well fracturing can use between an average of three to five million gallons of water each time the well is fractured. Without the ability to reuse the Frac water after the initial fracing, well producers must safely dispose of the contaminated Frac water and purchase additional non-contaminated Frac water for subsequent fracing of the well. These added costs can be quite significant considering that wells are often re-fractured multiple times over a period of several years.
It is therefore desirable to have a solution for properly recovering, treating, reusing, or disposing of Frac water in order to overcome the problems set forth above.